【摘要】 本文报导了十七个新的含氟烷基单取代环丙烷的核磁共振谱及质谱数据,着重讨论了含氟烷基对环上质子的屏蔽效应.烷基取代基中α碳(与环直接相联的碳)上的氢为氟原子取代之后,不仅使所有环上质子的化学位移向低场移动,并且使环上之顺式质子与反式质子的化学位移差Δδ减小,对应于三种类型的环丙烷:和相应的Δδ值分别为～0. 4、～0. 2和<0. 1ppm.这说明除了与环直接相联的 C-C 键外,与α碳相联的键(如 C-F 键)对环上质子的化学位移也有重大影响.文中对质谱也作了简单的讨论.更多还原

【Abstract】 NMR and mass spectral data of seventeen monosubstituted fluoroalkylcyclopropanesare presented; the shielding effect of the fluoroalkyl groups on the ring-protons arediscussed.Fluorine substitution on the carbon α to the ring not only deshields all thering protons,but also produces another interesting effect.Whereas ordinary alkylside-chain causes a difference in shielding on the cis and trans protons with a Δδ-valueof--0. 4ppm,the Δδ-values of the above mentioned cyclopropanes are a function of thenumber of fluorine atoms substituted on the α-carbon.The Δδ-values are～0. 4,～0. 2and <0. 1 ppm for the three types of cyclopropanes:（）-CH₂-R,（）-CHF-Rand（）-CF₂-R,respectively.Presumably,not only the diamagnetic anisotropy ofthe cyclopropyl-C_α bond,but also that of all the other bonds on C_α contribute to theshielding effects of the side-chain on the ring-protons.The mass spectra are also brieflydiscussed.更多还原